This invention relates to a Herschel-Quincke tube arrangement suitable for vehicle applications, and more particularly, the invention relates to a design and manufacture method and apparatus for producing a compact Herschel-Quincke tube arrangement.
Vehicle air intake systems route air from the environment to the engine for use in the combustion process. Air intake systems include a tube with an opening, typically located at the front of the vehicle proximate to the radiator, extending to the engine throttle. Various passive or active noise cancellation systems may be connected to the air intake and are located within the engine compartment, which because of their size may be difficult to package within the tight confines of modern engine compartments. Furthermore, increasing demands have been placed upon engine compartment space due to styling considerations and additional vehicle systems components.
Quarter wave tubes and Helmholtz resonators are commonly used to generate noise canceling pressure waves in passenger vehicles. Another type of passive noise cancellation structure is a Herschel-Quincke (HQ) tube, which provides superior noise cancellation to other passive noise cancellation systems. HQ tube arrangements cancel noise over a broader frequency band than either quarter wave tubes or Helmholtz resonators. HQ tubes have not been effectively used in passenger vehicle applications because they require a very large amount of space—much more space than is available within the confines of the engine compartment.
The challenge associated with packaging Herschel-Quincke tube arrangements in vehicles has not successfully been achieved for frequencies of a desired range. For example, prior art HQ arrangements have only attempted to tune frequencies between 1,000 to 3,000 Hz that only require short passages, and therefore is easier to fit within the vehicle.
Therefore, what is needed is a way of incorporating a noise cancellation system, such as an HQ tube, into a passenger vehicle to provide improved noise cancellation within the limited vehicle space.